A German published Pat. application No. 2,208,165 teaches a method for manufacturing hollow bodies out of thermoplastic materials. In a preforming station a blank is shaped around a blow mandrel, the blank with the blow mandrel is transferred to a blow station and therein is expanded in a divided blow mold by means of compressed air, is cooled, is solidified, and is removed from the blow mold. The blow mandrel is removed from the inflated hollow article prior to conclusion of the cooling by a relative motion between the blow mandrel and blow mold and immediately another conventional member feeding compressed air is brought to the opening in the hollow body for additional cooling.
The apparatus for performing this method consists of a preforming station, a blow station with a divided blow mold arranged at some distance from it, and a blow mandrel which can be moved back and forth between the preforming station and the blow station; it also includes equipment for the blowing and cooling of the hollow body. The blow mandrel and the other organs, which deliver compressed air in a similar manner, are arranged on a common guideway. These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.
It is, therefore, an outstanding object of the invention to simplify this known apparatus and to so develop it that the blow mandrel and the other compressed-air-feeding member execute only translational motions and take up a particularly well-defined spatial relationship to the different work stations.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.